Drier.



PATENTED MAY 24, 1904.

L. GA'I'HMANN.

N0 MODEL.

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the said process and-to be adapted to the dry- UNITED STATES PatentedMay 24, 1904.

PATENT OFFICE.

OF ONE-FOURTH TO ELDRED P. DI

OF WASHINGTON, DISTRICT OFCOLUMBIA DRI SPECIFICATION forming part ofLetters Application filed October l 1908.

To all whom it may concern,-

Be it known that I, LoUIs GATHMANN, a citizen of the United States,residing at Washington, in the District of Columbia, have invent- 5 edcertain new and useful Improvements in Driers; and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use IO the same, reference being bad to theaccompanying drawings, and to letters of reference marked thereon, whichform a part of this specification.

This invention relates to drying apparatus, and more particularly toapparatus for carrying out-the process described in my application for apatent of the United States filed on or about the 9th day of February,1903, Serial No. 142,653. An apparatus to carry out ing generally ofsubstances or materials, whether of natural or artificial derivation orproduction, should embody the following essential features, to wit: Aclosed circuit comprising a drying-chamber, means to interrupt thecontinuity of the circuit to substantially cut out said chamber, meansto produce a vapor-laden and vapor-saturated atmosphere in thedrying-chamber, means to induce circulation of the vaporous atmospherethrough the drying chamber and circuit, and means to restore the lostheat to the vaporous atmosphere in combination with means to lower thetemperature of the vaporous atmosphere to a con- (lensing temperatureafter it has passed out of contact with the substance or material to bedried, and means to graduate and regulate the condensation relatively tothe restored heat, so that the vaporous atmosphere will flow out ofcontact with the substance or material to be dried in a more or lesssaturated condition until near the end of the operation or until thevapor evolved from said substance or material is insufficient tosaturate the air, at which time the material will be dry internally,when condensation isor may be proceeded with substantially as fast asvapor is evolved from said substance or material, whereby the ex-CKINSON AND SOMERSET R. WVATERS,

Patent No. 761,041, dated May 24, 1904.

Serial No. 175,239. (No model.)

In the accompanying drawings I have illustrated a drier embodying theessential features above referred to, Figure 1 illustrating theapparatus in elevation, partly in section,on line 2 2 of Fig 2, whichlatter is a horizontal section on line 1 1 of Fig. 1.

Referring to the drawings, A indicates the drying apparatus; B, thedryingchamber, having an annular ledge b for the support, for instance,of a foraminous partition or basket (not shown) and containing thesubstance or material to be dried, the bottom of said chamber beingconical and having an outlet-pipe K, controlled by a valve K for drawingoff the condensate, and above said bottom is arranged a heater-condenserD. The lower part L of the drying-chamber, below the ledge b and abovethe heater-condenser D, is connected to the intake f of the casing F ofa fan-blower, whosedischarge f is connected to the lower end of theheating-space of a heater C of any suitable constructionas, forinstance, a tubular heater-whose tubes are supplied with a heatingmedium, as steam, through pipe connection C", such steam being exhaustedthrough pipe C, which may be a returnpipe to the boiler. (Not shown.)The heating-space of heater C is connected at its upper end by a pipe Pto the upper head of the drying-chamber, said pipe being provided with avalve V for controlling the flow of fluid to the drying-chamber B andfor interrupting the continuity of the circuit and practically cuttingsaid chamber out of said circuit, as it is obvious that when a basket,for instance, charged with material to be dried is suspended from theledge I) said basket practically forms a bottom for the chamber, whilethe lower part L of said drying-chamber becomes a heating or condensingchamber, as will be hereinafter more particularly explained.

For the purpose of controlling the supply of heating or cooling mediumto the heatercondenser D, I provide a separate vessel D, connected tosaid heater-condenser by a pipe provided with a valve D". The fluid tobe heated or the cooling agent is supplied to Vessel D throughvalve-controlled pipe (Z. The

ternal portions thereof are dried last.

vessel D is provided with burners, to which a suitable fuel, gaseous orliquid, is supplied through pipe (Z, having valve controlled branchpipes (Z leading to said burners. (Not shown.) I am thus enabled tosupply a heating medium to the heater-condenser D to gradually decreasethe temperature thereof or to supply a cooling medium to said heatercondenser of any desired or required low temperature for condensingpurposes, the heating or cooling agent being exhausted from thecondenser through pipe D, which may be a return-pipe to vessel D or to areceiver or condenser, according to the nature of the heating or coolingfluid supplied to vessel D.

The operation of the apparatus and the mode of procedure will in a greatmeasure depend upon the substance or material to be dried. If thesubstance or material to be dried contains quite a large percentage ofvaporizable matter, I produce a saturated atmosphere in thedrying-chamber by closing valve V and supplying heat to theheater-condenser D to heat the substance or material until a vaporizingtemperature has been produced and until sufficient vapor has beenevolved from the substance or material to saturate the atmosphereconfined in the drying-chamber. I then open the valve V, supply heat tothe heater 0, and set the fan in operation to cause the saturatedatmosphere to circulate through the drying-chamber B and circuit, and soregulate the heat supplied by said heater O as to maintain the saturatedatmosphere at a vaporizing temperature. I then lower the temperaturebelow the substance to be dried to a condensing temperature, whichlatter is then so regulated relativel y to the heat restored to thevaporous atmosphere as to gradually condense the vapors, so thattheatmosphere or air will at all times be vapor-laden after it passes outof the lower part L of the drying-chamber to be again heated to avaporizing temperature before it again passes into the drying-chamberproper until near the end of the operation or until the vapors evolvedfrom the substance are insufiicient to saturate the air, whencondensation can be carried on as fast as the said vapors are evolved bysuitably regulating the temperature in the lower part L of thedrying-chamber until the substance or material is dried. If, on theother hand, the substance or material is bulky, moreor less porous, anda poor conductor of heat, or when the substance is very dense andcontains a comparatively low percentage of vaporizable matter, I firstproduce a vaporous atmosphere in the drying-chamber by heat suppliedthrough the heater-condenser D while such atmosphere is confined in saidchamber. I then establish the circulation and gradually increase thetemperature of the vapor-laden atmosphere to heat the material throughand through until a vaporizing terrumrature has been reached to saturatethe atmbsphere and then begin condensation and proceed as abovedescribed, whereby surface drying and consequent imperfect drying andinjury to the substance or material are effectively avoided. I

I do, of course, not limitmyself to the form of the drying-chamberdescribed and shown, as this may be varied in accordance with the natureor character of the substance or material to be dried.

Having thus described my invention, what I claim as new therein,and-desire to secure by Letters Patent, is p 1. Apparatus comprising apipe-circuit including a drying-chamber, means to restore lost heat tothe circulating fluid and means to induce a forced circulation throughthe circuit; in combination with a heater-condenser in saiddrying-chamber and means to supply a heating or cooling agent to saidheater-condenser, for the purpose set forth.

2. Apparatus comprising a pipe-circuit including a drying-chamber, meansto restore lost heat to the circulating fluid, and means to induce aforced circulation through the circuit; in combination with aheater-condenser in said drying-chamber, means to supply a heating orcooling agent to said heater-condenser and means to cut thedrying-chamber out of the circuit, for the purpose set forth.

3. Apparatus comprising a pipe-circuit including a drying-chamber, meansto maintain a condensing temperature in the lower part of said chamber,means to induceaforced circulation downwardly through the chamber andback to the upper part thereof and means to restore lost heat to thecirculating fluid after it leaves the lower part of the chamber, for thepurposes set forth.

I. Apparatus comprising a pipe-circuit including a drying-chamber, aheater-condenser at the foot thereof, a heater interposed in the circuitbetween said heater-condenser and the upper end of the drying-chamberand means interposed in the circuit between the heatercondenser andheater to induce a forced circulation through said circuit, for thepurposes set forth.

5. Apparatus comprising a pipe-circuit including a drying-chamber, aheater and means between said heater and the lower part of thedrying-chamber to induce a forced circulation through the chamber,heater, and back to the upper part of said chamber; in combination witha heater-condenser in the lower part of said dryingchamber and a cutoffvalve between theupper part of said chamber and the first-named heater,for the purposes set forth.

In testimony that I claim the foregoing as my invention. I have signedmy name in presence of two subscribing witnesses.

LOUIS GATHMANN.

Witnesses:

HENRY ORTH, J r., B. W. SoMMuRs.

